The second-degree murder charge against Fort Collins' Nicole Marie Ryan will likely be a complicated one to prove. The facts on the surface seem simple: Ryan appears to have slashed the throat of her fiance, Raymond Wimmer, who later bled to death. But this act was prefigured by a back story involving a record of domestic abuse that's only starting to emerge.

The heavy lifting on this story has been done by the Fort Collins Coloradan, which reported that at about 11:25 p.m. on October 5, Ryan, who's 23, called 911 to say that she'd injured a person she described as her husband, although she and the dead man, thirty-year-old Raymond Neal Wimmer, were engaged but not yet wed.

The house where the incident took place.

Wimmer had been injured, all right, as indicated by the slit across his throat. By the time emergency crews arrived at the address, on the 400 block of North Meldrum Street in FoCo, and transported him to a nearby hospital, he'd already expired.

The incident reportedly took place in a basement bedroom of a home where Ryan's mom, her brother and another roommate also lived. But no one other than Ryan and Wimmer were around when the knife came out. However, a woman who attended Ryan's bond hearing this week told the Coloradoan that Wimmer had threatened to leave Ryan during an alcohol-fueled argument before the fatal incident, prompting her to "attack" him.

Whatever actually happened on the night in question, there's no doubt that both Ryan and Wimmer had previous interactions with police. But the main black mark on her record isn't a violent crime.

According to the Coloradoan, Ryan earned a two-year deferred sentence in relation to a 2008 case involving alleged false statements about prescribed drugs and small-time (under $500) theft. And Wimmer? He racked up a number of restraining orders -- among them one for domestic assault against his former wife.

Will Ryan claim Wimmer had been assaulting her, and that she acted in self-defense? It's too soon to know. In the meantime, she remains behind bars on second-degree-murder and domestic-violence charges. Here's a larger look at her mug shot, as well as an earlier booking photo of Wimmer.